Elastic sheet for absorbent article and absorbent article

Patent metadata

Field	Value
Publication number	US-11925540-B2
Application number	US-202016845450-A
Country	US
Kind code	B2
Filing date	Apr 10, 2020
Priority date	Oct 12, 2017
Publication date	Mar 12, 2024
Grant date	Mar 12, 2024

Abstract

An elastic sheet for an absorbent article includes a first fibrous layer disposed on a first surface of the elastic sheet, a second fibrous layer disposed on a second surface of the elastic sheet opposite to the first surface, and contractible elastic members secured between the first fibrous layer and the second fibrous layer. The first fibrous layer and the second fibrous layer each include continuous fibers of thermoplastic and gathers formed between adjacent ones of the elastic members. The gathers are disposed in an intersecting direction intersecting with a direction in which the elastic members extend. An average flexural rigidity value of the first fibrous layer and the second fibrous layer in accordance with a KES method is 0.0035×10−4 to 0.022×10−4 (N·m2/m). A thickness under a compression load to the gathers in accordance with the KES method is 0.22 to 1.5 mm.

First claim

What is claimed is:

1. The elastic sheet for an absorbent article comprising:
a first fibrous layer comprising a first surface of the elastic sheet;
a second fibrous layer comprising a second surface of the elastic sheet opposite the first surface; and
contractible elastic members extending in a first direction and secured between the first fibrous layer and the second fibrous layer, the first fibrous layer and the second fibrous layer having a plurality of gathers disposed in a second direction intersecting the first direction and also formed between elastic members,
wherein the first fibrous layer comprises a spun-bonded or spun-melt nonwoven fabric including continuous polyethylene fibers and wherein a second fibrous layer comprises a spun-bonded or spun-melt nonwoven fabric including continuous polyethylene and/or polypropylene fibers,
an average flexural rigidity value of the first fibrous layer and second fibrous layer is 0.0035×10 −4 to 0.022×10 −4 N·m 2 /m as measured according to a Kawabata Evaluation System (KES) method, and
a thickness of 0.22 to 1.5 mm under a compression load of 49.03 hPa to the gathers as measured according to a KES method.

2. The elastic sheet according to claim 1 , comprising an initial thickness of 2.70 to 4.70 mm under a micro-load to the gathers of 0.49 hPa according to the KES method.

3. The elastic sheet according to claim 1 , wherein
the gathers between adjacent elastic members are formed such that a convexity is formed as viewed from the first surface and a concavity is formed as viewed from the second surface.

4. The elastic sheet according to claim 1 , wherein
a compression workload under the compression load to the gathers is 0.236 to 5.0 N·m/m 2 , and
a compression resilience rate under the compression load to the gathers is 19 to 36%.

5. The elastic sheet according to claim 1 , wherein
the first fibrous layer and the second fibrous layer each comprise fused parts, where the continuous fibers are fused, and non-fused parts, wherein a rigidity difference between the fusion parts and non-fused parts in the second fibrous layer is larger than a rigidity difference between the fused parts and the non-fused parts.

6. The elastic sheet according to claim 1 , wherein
a basis weight of each of the first fibrous layer and the second fibrous layer is 10 to 30 g/m 2 ,
a density of each of the first fibrous layer and the second fibrous layer is 0.04 to 0.15 g/m 3 , and
a pitch between the elastic members in the intersecting direction is 2.0 to 12.0 mm.

7. The elastic sheet according to claim 1 , wherein a fineness of the polyethylene fibers is 1.5 to 4.0 dtex and a fineness of the polypropylene fibers, if present, is 0.9 to 2.5 dtex.

8. An absorbent article comprising the elastic sheet according to claim 1 , wherein
the first surface is a skin-facing surface, and
the second surface is a non-skin facing surface opposite to the skin facing surface.

9. The absorbent article according to claim 8 , wherein
the absorbent article is a disposable diaper having a front waist region, a rear waist region, and a crotch region, wherein
the elastic sheet forms one or more of a waist elastic sheet forming the front and rear waist regions, a leg elastic sheet disposed along a leg opening edge in the crotch region, and a leakage barrier flap extending from the crotch region to the front and rear waist regions.

10. The elastic sheet for an absorbent article comprising:
a first fibrous layer comprising a first surface of the elastic sheet;
a second fibrous layer comprising a second surface of the elastic sheet opposite the first surface; and
contractible elastic members extending in a first direction and secured between the first fibrous layer and the second fibrous layer, the first fibrous layer and the second fibrous layer having a plurality of gathers disposed in a second direction intersecting the first direction and also formed such that a convexity is formed as viewed from the first surface and a concavity is formed as viewed from the second surface between adjacent elastic members,
wherein the first fibrous layer and the second fibrous layer comprise a spun-bonded or spun-melt nonwoven fabric including continuous thermoplastic fibers;
an average flexural rigidity value of the first fibrous layer and second fibrous layer is 0.0035×10 −4 to 0.022×10 −4 N·m 2 /m as measured according to a Kawabata Evaluation System (KES) method, and
a thickness under a compression load of 49.03 hPa to the gathers is 0.22 to 1.5 mm as measured according to a KES method.

11. The elastic sheet according to claim 10 , comprising an initial thickness of 2.70 to 4.70 mm under a micro-load to the gathers of 0.49 hPa according to the KES method.

12. The elastic sheet according to claim 10 , wherein
wherein the thermoplastic fibers are polyethylene fibers for the first fibrous layer and wherein the thermoplastic fibers are polyethylene and/or polypropylene fibers for the second fibrous layer.

13. The elastic sheet according to claim 10 , wherein
a compression workload under the compression load to the gathers is 0.236 to 5.0 N·m/m 2 , and
a compression resilience rate under the compression load to the gathers is 19 to 36%.

14. The elastic sheet according to claim 10 , wherein
the first fibrous layer and the second fibrous layer each comprise fused parts, where the continuous fibers are fused, and non-fused parts, wherein a rigidity difference between the fusion parts and non-fused parts in the second fibrous layer is larger than a rigidity difference between the fused parts and the non-fused parts.

15. The elastic sheet according to claim 10 , wherein
a basis weight of each of the first fibrous layer and the second fibrous layer is 10 to 30 g/m 2 ,
a density of each of the first fibrous layer and the second fibrous layer is 0.04 to 0.15 g/m 3 , and
a pitch between the elastic members in the intersecting direction is 2.0 to 12.0 mm.

16. The elastic sheet according to claim 12 , wherein a fineness of the polyethylene fibers is 1.5 to 4.0 dtex and a fineness of the polypropylene fibers, if present, is 0.9 to 2.5 dtex.

17. An absorbent article comprising the elastic sheet according to claim 10 , wherein
the first surface is a skin-facing surface, and
the second surface is a non-skin facing surface opposite to the skin facing surface.

18. The absorbent article according to claim 17 , wherein
the absorbent article is a disposable diaper having a front waist region, a rear waist region, and a crotch region, wherein
the elastic sheet forms one or more of a waist elastic sheet forming the front and rear waist regions, a leg elastic sheet disposed along a leg opening edge in the crotch region, and a leakage barrier flap extending from the crotch region to the front and rear waist regions.

19. The elastic sheet for an absorbent article comprising:
a first fibrous layer comprising a first surface of the elastic sheet;
a second fibrous layer comprising a second surface of the elastic sheet opposite the first surface; and
contractible elastic members extending in a first direction and secured between the first fibrous layer and the second fibrous layer, the first fibrous layer and the second fibrous layer having a plurality of gathers disposed in a second direction intersecting the first direction and also formed between elastic members,
wherein the first fibrous layer and the second fibrous layer comprise a spun-bonded or spun-melt nonwoven fabric including continuous thermoplastic fibers, where

Assignees

• Unicharm Corp

Inventors

• Ikeuchi Norihito
• Mitsuno Satoshi

Classifications

• A61F13/49012 Primary

  the elastic means being elastic panels · CPC title

• A61F13/4902

  characterised by the elastic material · CPC title

• A61F13/4942

  the barrier not being integral with the top- or back-sheet · CPC title

• B32B3/18 Primary

  characterised by an internal layer formed of separate pieces of material {which are juxtaposed side-by-side (B32B5/02 takes precedence)} · CPC title

• B32B3/22

  of spaced pieces {(not used)} · CPC title